Most modern bicycles have a seat attachment device that inserts into the frame of the bicycle and may be tightened in order to secure a saddle for the bicycle to the frame of the bicycle. A conventional bicycle seat assembly 80 is shown in FIGS. 1 and 2 and generally includes a seat 81, a post 82 and a securing device for connecting the seat 81 to the post 82. The securing device includes a top bracket 84 connected to the underside of the seat 81 and a lower bracket 85 which is fixed on a top of the post 82. Two rails 83 are clamped between the top bracket 84 and the lower bracket 85. Two bolts 86 extend through two transverse bars connecting the top bracket 84 and the lower bracket 85 to pull the top bracket 84 and the lower bracket 85 toward each other so that the two rails 83 are securely clamped. It is noted that the two bolts 86 are threaded through the two bars from in top bracket 84 so that it is difficult to adjust the angle of the seat relative to the post 82. In addition, the shocks from the roads are transferred along the post 82 to the seat 81 and the direction that the shocks are transferred is the same as the bolts 86 which are easily loosened by the shocks. Thus, it is desirable to provide a seat attachment device that overcomes these limitations of the current seat attachment device and it is to this end that the present invention is directed.